It is important to know where you are going, before you put down that first brushstroke. You can do that by value studies and color studies. You can also do that by looking at your painting and rehearsing where that stroke is going to go and what colors are going to be added to that stroke. Some artists will dance their brush above their painting, practicing that stroke before it ever touches the painting.
It is also important to know where the whites are going to be in your painting and doing something to help you preserve those whites. I like to draw a circle on my paper where I want to save those whites. This way they don’t get covered up in the exuberance of putting down those fresh washes. The dance of white in your watercolors add life to your paintings.
Both of these paintings were started as demos in my watercolor class. Talking and painting at the same time is a skill that takes time to learn. You don’t know what will come out of your mouth nor what will go down on the paper. It’s always an adventure.